Neuroactive Steroids in Acute Ischemic Stroke

Overview

Acute ischemic stroke (AIS) represents an economical challenge for health systems all over the globe. Despite increasing knowledge of the pathophysiology of AIS, there is no satisfactory treatment to revert the resulting brain damage. Changes of neuroactive steroids have been found in different neurological diseases. In this regard, the investigators have previously demonstrated that old patients with AIS show changes of plasma cortisol and estradiol concentrations, in that increased steroid levels are associated with a deterioration of neurological status and a worse cognitive decline. The present study assessed in patients with AIS if changes of behavior, brain-derived neurotrophic factor (BDNF) and nitrites (NO-2) (nitric oxide soluble metabolite) bear a relationship with the degree of hypercortisolism. To this purpose, the investigators recruited patients hospitalized at the Central Military Hospital emergency room within the first 24 hours of AIS. Subjects were divided into two groups, each one composed of 40 control subjects and 40 AIS patients, including men and women. The neurological condition was assessed using the NIHSS and the cognitive status with the Montreal Cognitive Assessment (MoCA test). The emotional status was evaluated using the Montgomery-Asberg Depression Rating Scale (MADRS), whereas the Modified Rankin Scale (MRS) was used to determine the functional condition. BDNF and NO-2 plasma levels were measured by ELISA and the Griess reaction method, respectively.

Acute Ischemic Stroke (AIS) is one of the main causes of functional deterioration all over the world. Thus, 26% of patients older than 65 years still show limitations of daily activities 6 months after AIS, and 46% of these patients present cognitive deficiency of variable severity. AIS impose a burden on the way of living of patients and their families' in which depression emerges as a frequent neuropsychiatric disorder after the ischemic event. However, the occurrence of depression and other functional abnormalities on the first day following AIS is largely unknown. Neuroactive steroids have the capability to modulate in a positive or negative way the function of the nervous system. Changes in neuroactive steroid concentrations in plasma and nervous system have been described in degenerative diseases (Parkinson's disease, Alzheimer's disease, Huntington's disease, amyotrophic lateral sclerosis), autoimmune diseases (multiple sclerosis), epilepsy, and psychiatric disorders (depression and schizophrenia). In vulnerable regions such as the hippocampus and prefrontal cortex, high cortisol exposure damages the pyramidal neurons, decreases neurogenesis and impairs memory and learning. In a previous report, the investigators have demonstrated that old patients with AIS show changes in the plasma levels of cortisol and estradiol, which associate with low cognition, worse neurological status, and poor functional performance. The present report investigated changes of cortisol, brain-derived neurotrophic factor (BDNF) and nitrites (NO-2, nitric oxide soluble metabolites) after AIS. BDNF is a neurotrophin classically associated with learning and memory and negatively modulated by glucocorticoids, old age, and neurodegenerative diseases. In plasma, platelets are the major source of peripheral BDNF and levels of this neurotrophin are decreased in Alzheimer´s disease and depression. These disorders also show hypercortisolism and changes of cortisol dynamics suggesting that steroids, neurotrophins, and behavioral deficits may be functionally related. Regarding nitrites, cortisol treatment of human subjects significantly reduced plasma nitrate/nitrite concentrations. Therefore, considering that opposite changes occur in cortisol vs. BDNF and nitrites, the investigators aimed to determine in acute AIS patients (a) changes in plasma cortisol; (b) development of clinical, behavioral and functional deficits; (c) changes in plasma BDNF and nitrites, which may predict a neurotoxic effect of the excess cortisol in the ischemic nervous system.